[PATCH 1/2] lib/Kconfig.debug: Make TEST_LOCKUP depend on module

[PATCH 1/2] lib/Kconfig.debug: Make TEST_LOCKUP depend on module

[Tiezhu Yang]

Since test_lockup is a test module to generate lockups, it is better to
limit TEST_LOCKUP to module (=m) or disabled (=n) because we can not use
the module parameters when CONFIG_TEST_LOCKUP=y.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 lib/Kconfig.debug | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 9ad9210..18b7c67 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1035,6 +1035,7 @@ config WQ_WATCHDOG
 
 config TEST_LOCKUP
 	tristate "Test module to generate lockups"
+	depends on m
 	help
 	  This builds the "test_lockup" module that helps to make sure
 	  that watchdogs and lockup detectors are working properly.
-- 
2.1.0

[PATCH 2/2] lib/test_lockup.c: Fix return value of test_lockup_init()

[Tiezhu Yang]

Since filp_open() returns an error pointer, we should use IS_ERR() to
check the return value and then return PTR_ERR() if failed to get the
actual return value instead of always -EINVAL.

E.g. without this patch:

[root@localhost loongson]# ls no_such_file
ls: cannot access no_such_file: No such file or directory
[root@localhost loongson]# modprobe test_lockup file_path=no_such_file lock_sb_umount time_secs=60 state=S
modprobe: ERROR: could not insert 'test_lockup': Invalid argument
[root@localhost loongson]# dmesg | tail -1
[  126.100596] test_lockup: cannot find file_path

With this patch:

[root@localhost loongson]# ls no_such_file
ls: cannot access no_such_file: No such file or directory
[root@localhost loongson]# modprobe test_lockup file_path=no_such_file lock_sb_umount time_secs=60 state=S
modprobe: ERROR: could not insert 'test_lockup': Unknown symbol in module, or unknown parameter (see dmesg)
[root@localhost loongson]# dmesg | tail -1
[   95.134362] test_lockup: failed to open no_such_file: -2

Fixes: aecd42df6d39 ("lib/test_lockup.c: add parameters for locking generic vfs locks")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 lib/test_lockup.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/test_lockup.c b/lib/test_lockup.c
index bd7c7ff..e720276 100644
--- a/lib/test_lockup.c
+++ b/lib/test_lockup.c
@@ -512,8 +512,8 @@ static int __init test_lockup_init(void)
 	if (test_file_path[0]) {
 		test_file = filp_open(test_file_path, O_RDONLY, 0);
 		if (IS_ERR(test_file)) {
-			pr_err("cannot find file_path\n");
-			return -EINVAL;
+			pr_err("failed to open %s: %ld\n", test_file_path, PTR_ERR(test_file));
+			return PTR_ERR(test_file);
 		}
 		test_inode = file_inode(test_file);
 	} else if (test_lock_inode ||
-- 
2.1.0

Re: [PATCH 1/2] lib/Kconfig.debug: Make TEST_LOCKUP depend on module

[Guenter Roeck]

On 7/23/20 6:50 PM, Tiezhu Yang wrote:
> Since test_lockup is a test module to generate lockups, it is better to
> limit TEST_LOCKUP to module (=m) or disabled (=n) because we can not use
> the module parameters when CONFIG_TEST_LOCKUP=y.
> 
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>

Makes sense.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  lib/Kconfig.debug | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 9ad9210..18b7c67 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1035,6 +1035,7 @@ config WQ_WATCHDOG
>  
>  config TEST_LOCKUP
>  	tristate "Test module to generate lockups"
> +	depends on m
>  	help
>  	  This builds the "test_lockup" module that helps to make sure
>  	  that watchdogs and lockup detectors are working properly.
> 

Re: [PATCH 2/2] lib/test_lockup.c: Fix return value of test_lockup_init()

[Guenter Roeck]

On 7/23/20 6:50 PM, Tiezhu Yang wrote:
> Since filp_open() returns an error pointer, we should use IS_ERR() to
> check the return value and then return PTR_ERR() if failed to get the
> actual return value instead of always -EINVAL.
> 
> E.g. without this patch:
> 
> [root@localhost loongson]# ls no_such_file
> ls: cannot access no_such_file: No such file or directory
> [root@localhost loongson]# modprobe test_lockup file_path=no_such_file lock_sb_umount time_secs=60 state=S
> modprobe: ERROR: could not insert 'test_lockup': Invalid argument
> [root@localhost loongson]# dmesg | tail -1
> [  126.100596] test_lockup: cannot find file_path
> 
> With this patch:
> 
> [root@localhost loongson]# ls no_such_file
> ls: cannot access no_such_file: No such file or directory
> [root@localhost loongson]# modprobe test_lockup file_path=no_such_file lock_sb_umount time_secs=60 state=S
> modprobe: ERROR: could not insert 'test_lockup': Unknown symbol in module, or unknown parameter (see dmesg)
> [root@localhost loongson]# dmesg | tail -1
> [   95.134362] test_lockup: failed to open no_such_file: -2
> 
> Fixes: aecd42df6d39 ("lib/test_lockup.c: add parameters for locking generic vfs locks")
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  lib/test_lockup.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/test_lockup.c b/lib/test_lockup.c
> index bd7c7ff..e720276 100644
> --- a/lib/test_lockup.c
> +++ b/lib/test_lockup.c
> @@ -512,8 +512,8 @@ static int __init test_lockup_init(void)
>  	if (test_file_path[0]) {
>  		test_file = filp_open(test_file_path, O_RDONLY, 0);
>  		if (IS_ERR(test_file)) {
> -			pr_err("cannot find file_path\n");
> -			return -EINVAL;
> +			pr_err("failed to open %s: %ld\n", test_file_path, PTR_ERR(test_file));
> +			return PTR_ERR(test_file);
>  		}
>  		test_inode = file_inode(test_file);
>  	} else if (test_lock_inode ||
>